1. Field of the Invention
The present invention relates to a monitoring method and a monitor apparatus capable of readily obtaining data necessary for the generation of an alarm; for example, determining the distance to a moving object which has entered a monitor region, by means of an image processing technique.
2. Description of the Related Art
Conventional monitor apparatuses which use an image processing technique to detect the entry of a moving object into a specific indoor or outdoor monitor region are in widespread use. In a monitor apparatus of this type, in order to detect an object entering a monitor region, a difference between an initial image when no entering object is present and the monitoring image is obtained. In the monitor apparatus, an object entering its monitor region is detected, an alarm is preferably generated, and data associated with a distance to the object is preferably detected. In addition, the dimensions of the object are preferably detected.
However, in order to detect the distance to or the dimensions of an entering object, a plurality of image pickup devices must be used to stereoscopically monitor the object, and the data obtained must be subjected to three-dimensional image processing, which is a complicated operation. Satisfying this requirement results in a monitor apparatus which is undesirably complex and bulky, and, inevitably expensive. Japanese Unexamined Patent Disclosure No. 62-65182 proposes a technique in which sampling rates for remote and local points with respect to an object image obtained in a field of view of one image pickup device are varied, and the sampling rates for remote points are segmented more finely than local points, thereby performing object recognition with respect to distance. However, with this technique, the distance to the object of the dimensions of the object cannot be detected.